I'm a very beginner hobby photographer so apologies in advance if I'm doing something silly. I've had a dslr for a few months and I worked my way through understanding different aspects and I'm generally happy with my progress.

I recently bought a Speedlite 430 EX II so I could play around with it a bit more in darker situations. I'm already happy with it because it lets me use faster shutter speeds in the night and still get good bright images - previously I had to use slow shutter speed and more often than not the image would be blurry.

My problem is, when I'm shooting in manual mode, I use the on-camera screen to preview the image, and I set the aperture speed, focal length, ISO to where I'm happy and I just take the photo when it's ready, and the final image is exactly as I saw on screen when setting it up.

Now, with the flash though, the final image is always brighter (which is good), but the thing is, I don't really know how much brighter it will be! I always have to take a good 2-3 pictures, check the final image, and then set my aperture / ISO until it is good... if I move back or change angle, I have to repeat the process. I can't find how people use flash like this on youtube etc.

I am guessing it would not be possible for my camera to show what the image would be like with the flash when I'm setting it up... so how do people work with a flash gun and manual mode please?

Please note that I'm still not fully comfortable with the speedlite and I'm still learning, and so far, I've only used the speedlite in full auto mode and my camera is in manual.

  • \$\begingroup\$ Flash and manual mode can be somewhat complicated. That's why through-the-lens metering was invented. Let the camera figure it out! \$\endgroup\$ Commented Jan 17 at 14:38
  • 1
    \$\begingroup\$ For manual exposure with flash you need to learn about guide numbers. \$\endgroup\$ Commented Jan 17 at 14:44
  • \$\begingroup\$ If you have a 430EX the fastest way to get results is to use "P" mode with the flash. \$\endgroup\$
    – xenoid
    Commented Jan 17 at 18:34

3 Answers 3


Exposure time does not really matter when you use a flash, as that is usually your only (or at least main) source of light. You set it to about 1/60 s, just long enough to get all of the flash.

As you want to go fully manual, it helps to look at an old flash. This is the back side of a Minolta Auto 360PX from the 80s:

Minolta Auto 360PX

The only thing you can really set in manual mode is the flash power.

The wheels are just a calculator. E.g. you select ISO, aperture, whether you put a tele or wide angle panel in front of the flash (T/none/W1/W2), and power level - and you get the distance for correct exposure.

Earlier, they made these flash exposure calculator wheels out of paper, you can still find some on ebay.

Further reading:

  • \$\begingroup\$ corrected description of T/N/W1/W2 setting \$\endgroup\$
    – user24582
    Commented Jan 22 at 21:10

The best way to use your flash is with the camera in Manual mode, and with the flash set to ETTL mode.

Indoors I always use bounce flash as it is much more natural looking than straight ahead flash.

You can’t see what the final image will look like before the photo is taken, but the Camera can. The camera uses an ETTL a Pre-Flash to fine tune the exposure BEFORE the actual exposure takes place. The Pre-Flash takes place immediately before the main flash and is usually not noticeable.

One good piece of advice I learned many years ago is that when using a flash, there are actually TWO simultaneous exposures made. Every scene you shoot will have both a Ambient lighting and Flash lighting component. You can vary the balance the Ambient lighting exposure and Flash lighting exposure, by varying the camera’s Manual exposure with shutter speed and aperture, and the ETTL Flash exposure using +/- Exposure Compensation.

I often start with ISO 400 1/125 f/5.6 in Manual mode, and then meter the scene with the flash turned off. I then adjust the the variables so that the camera’s exposure meter shows about -2 or -1 EV exposure. This will be the Ambient exposure.

Then I turn on the flash and start shooting. The Flash Exposure Compensation can then be used to fine tune the overall exposure.

If you are using a DSLR with LiveView, instead of the optical viewfinder, most (not all) cameras will give you the option to see LiveView with Exposure Simulation turned on or off. Having it off will give you a nice bright screen to compose your shot, but you won’t be able to use it to judge the ambient exposure.

I imagine Mirrorless cameras also have this option for Exposure Simulation in the digital viewfinder.


No, you cannot see light that does not exist at the time.

And since the light from the flash does not fall evenly everywhere, it cannot be simulated with screen brightness.

  • \$\begingroup\$ yes of course, I get that - my question is about how people usually work with this condition. Are there any guide lines or rules that I can use to predict / calculate what my aperture and shutter speed should be when I'm using a flash \$\endgroup\$ Commented Jan 17 at 15:12
  • \$\begingroup\$ Experience mostly... if using TTL flash metering you will generally want to dial in a little negative flash exposure compensation (~1stop) after you have set your manual ambient exposure. \$\endgroup\$ Commented Jan 17 at 17:17

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